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Hisham Hafeez
Subject: Science
, asked on 22/2/18
Please Answer both the Questions
1) a. Give reason for the following:
(i) Isotopes of an element are chemically similar.
(ii) Noble gases show least reactivity.
b. If K and L shells of an atom are full, then what would be the total number of electrons in the atom ? what is the valency of this element ?
c. write the electronic configuration of an element with atomic number 13 and represent it in terms of Bohr's model of atom.
2)a. Which among the following has more number of molecules :
1g of hydrogen (H
2
) or 1g of methane (CH
?4
) ? (Atomic mass of H = 1u, C = 12u)
b. Calculate the number of particles in 46g of Na atoms. (Atomic mass of Na = 23u)
c.Write the names of the compounds represented by the following formulae:
(i) Na
2
S (ii) (NH
4
)
2
CO
3
d. Write the chemical formula of :
(i) Magnesium hydroxide (ii) Aluminium chloride
Answer
2
Hisham Hafeez
Subject: Science
, asked on 22/2/18
1) a. What is the relationship between two elements X and Y whose atomic numbers are 18 and 20 respectively but their mass numbers remain same as 40 ?
b. Are their chemical properties same or different? Justify your answer.
c. Which has more number of electrons Na or Na
+
? Why ?
2) a. Give reason for the following:
(i) Isotopes of an element are chemically similar.
(ii) Noble gases show least reactivity.
b. If K and L shells of an atom are full, then what would be the total number of electrons in the atom ? what is the valency of this element ?
c. write the electronic configuration of an element with atomic number 13 and represent it in terms of Bohr's model of atom.
3)a. Which among the following has more number of molecules :
1g of hydrogen (H
2
) or 1g of methane (CH
4
) ? (Atomic mass of H = 1u, C = 12u)
b. Calculate the number of particles in 46g of Na atoms. (Atomic mass of Na = 23u)
c.Write the names of the compounds represented by the following formulae:
(i) Na
2
S (ii) (NH
4
)
2
CO
3
d. Write the chemical formula of :
(i) Magnesium hydroxide (ii) Aluminium chloride
Experts plz answer ASAP!!!!
Answer
1
Devanshi Hassija
Subject: Science
, asked on 21/2/18
How can I study 15 chapters of science in one day ?
Answer
4
Esther
Subject: Science
, asked on 21/2/18
Solve this:
Q.24. (a) Describe the main features of Bohr's model of an atom. Draw a neat and labelled diagram of energy levels.
Answer
1
Adyasha Soumya Routray
Subject: Science
, asked on 18/2/18
5. The atomic mass of element 39. No. of neutron is 20.
(i) Find the vasence cell electron and valency of atom
(ii) Represent the electric configuration of it.
(iii) When the same metal reacts with non-metal like chlorine write the molecular formula.
Answer
2
Apurva Kumari
Subject: Science
, asked on 17/2/18
Why it was essential to make isotopes and isobars?
Answer
1
Talib Kausar Faridy
Subject: Science
, asked on 16/2/18
state the two prostulates put forward by E. Rutherford about the structure of atom based on alpha particles scattering experiment.
Answer
1
Rishika
Subject: Science
, asked on 15/2/18
Q.4. Write the molecular formula of all the compounds using criss-cross method, that can be formed by the combination of the following ions
a. Potassium ion
b. nitrate ion
c. carbonate ion
d. magnesium ion
Answer
2
Vaishnavi G
Subject: Science
, asked on 14/2/18
Q.(b). Write the electronic configuration of elements- K(19), N(7), S(16).
Answer
4
Vaishnavi G
Subject: Science
, asked on 14/2/18
Q). Write the electronic configuration for an atom whose atomic number is 12 and mass 24. Show it by drawing a figure.
Answer
3
Vaishnavi G
Subject: Science
, asked on 14/2/18
7th fast
Q.7. Write the electronic configuration for an atom whose atomic number is 12 and mass 24. Show it by drawing a figure.
Answer
1
Vaishnavi G
Subject: Science
, asked on 14/2/18
Q8 (a) What do you mean by valence electron?
(b) Write the electronic configuration of element - K(19), N(7), S(16)
Q9. Define
(a) Atomic number
(b) Isotopes.
(c) Isobars
Answer
3
Vaishnavi G
Subject: Science
, asked on 14/2/18
Q6. Draw the sketch of Bohr's model of an atom with three shells.
Q7. Write the electronic configuration for an atom whose atomic number is 12 & mass 2
μ
. show it by drawing a figure
Answer
2
Vaishnavi G
Subject: Science
, asked on 14/2/18
4,5 please
Answer
2
Vaishnavi G
Subject: Science
, asked on 14/2/18
1,2,3 solve fast
Answer
3
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What are you looking for?
1) a. Give reason for the following:
(i) Isotopes of an element are chemically similar.
(ii) Noble gases show least reactivity.
b. If K and L shells of an atom are full, then what would be the total number of electrons in the atom ? what is the valency of this element ?
c. write the electronic configuration of an element with atomic number 13 and represent it in terms of Bohr's model of atom.
2)a. Which among the following has more number of molecules :
1g of hydrogen (H2) or 1g of methane (CH?4) ? (Atomic mass of H = 1u, C = 12u)
b. Calculate the number of particles in 46g of Na atoms. (Atomic mass of Na = 23u)
c.Write the names of the compounds represented by the following formulae:
(i) Na2S (ii) (NH4)2CO3
d. Write the chemical formula of :
(i) Magnesium hydroxide (ii) Aluminium chloride
b. Are their chemical properties same or different? Justify your answer.
c. Which has more number of electrons Na or Na+ ? Why ?
2) a. Give reason for the following:
(i) Isotopes of an element are chemically similar.
(ii) Noble gases show least reactivity.
b. If K and L shells of an atom are full, then what would be the total number of electrons in the atom ? what is the valency of this element ?
c. write the electronic configuration of an element with atomic number 13 and represent it in terms of Bohr's model of atom.
3)a. Which among the following has more number of molecules :
1g of hydrogen (H2) or 1g of methane (CH4) ? (Atomic mass of H = 1u, C = 12u)
b. Calculate the number of particles in 46g of Na atoms. (Atomic mass of Na = 23u)
c.Write the names of the compounds represented by the following formulae:
(i) Na2S (ii) (NH4)2CO3
d. Write the chemical formula of :
(i) Magnesium hydroxide (ii) Aluminium chloride
Experts plz answer ASAP!!!!
Q.24. (a) Describe the main features of Bohr's model of an atom. Draw a neat and labelled diagram of energy levels.
(i) Find the vasence cell electron and valency of atom
(ii) Represent the electric configuration of it.
(iii) When the same metal reacts with non-metal like chlorine write the molecular formula.
a. Potassium ion
b. nitrate ion
c. carbonate ion
d. magnesium ion
Q.7. Write the electronic configuration for an atom whose atomic number is 12 and mass 24. Show it by drawing a figure.
(b) Write the electronic configuration of element - K(19), N(7), S(16)
Q9. Define
(a) Atomic number
(b) Isotopes.
(c) Isobars
Q7. Write the electronic configuration for an atom whose atomic number is 12 & mass 2. show it by drawing a figure